JP4453597B2 - Optical device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical device and a manufacturing method thereof, and more specifically to an optical device including an optical element and a low-loss optical waveguide and a manufacturing method thereof.

  Patent Document 1 describes an optical product assembling method in which a laser element and a wavelength conversion element are optically aligned and fixed with a certain gap. That is, the wavelength conversion element mount is positioned parallel to the laser element mount with a predetermined gap (20 μm). The optical axis of the wavelength conversion element is adjusted with respect to the laser element fixed to the laser element mount, and they are fixed to each other with an ultraviolet curable adhesive. The wavelength conversion element is fixed to the wavelength conversion element mount with an ultraviolet curable adhesive. Then, an anaerobic ultraviolet curable adhesive is inserted into the gap between the laser element mount and the wavelength conversion element mount and fixed to each other.

Further, in Patent Document 2, the optical waveguide and the optical element are arranged so that the optical path between the optical waveguide and the optical element is in a recess, and the recess has a fluid permeability that approximates the refractive index of the optical waveguide. A three-layer structure is described in which it is filled with a light-sensitive resin (inner resin), the inner resin is covered with a flexible intermediate resin, and intermediate reception is covered with a hard outer resin.
JP 2003-046184 A JP 2001-305393 A

  In the method described in Patent Document 1, when only two optical elements are fixed to face each other at a short distance in order to optically couple, the reflected return light from the end face of the optical element is transmitted to another optical element, for example, a laser element. Incident light causes noise. In particular, when the distance between the optical elements is short, the influence of externally reflected return light becomes strong.

  The reflected return light intensity is determined by the refractive index difference. By reducing the difference in refractive index between both sides of the end face, the return loss (ORL) can be reduced. For this purpose, the space of the optical coupling portion may be filled with a transparent material having a refractive index approximate to the refractive index of the optical waveguide or the optical element. Optically transparent resins include silicone-based, epoxy-based, and acrylate-based resins with a refractive index of 1.3 to 1.7. For example, when light enters the optical waveguide having a refractive index = 1.48 from the air (refractive index = 1.0), the ORL is −14.3 dB, but the acrylate resin has a refractive index of 1.5 at room temperature. Is applied, the ORL becomes -43.4 dB.

  However, if the space between the two optical elements and the periphery thereof are filled with a cured resin, the optical element is subjected to stress due to thermal expansion, and the optical element is deteriorated or damaged. In order to avoid this, in Patent Document 2, a fluid transparent resin is used, but as a result, a three-layer structure must be adopted, which complicates the manufacturing process.

  An object of the present invention is to provide an optical device that does not cause such inconvenience and a method for manufacturing the same.

An optical device according to the present invention includes a first optical element fixed to a first mount, a second optical element fixed to a second mount, an optical coupling surface of the first optical element, and the An adhesive member for fixing the first and second mounts so as to face the optical coupling surface of the second optical element, and a transparent resin (28) that fills the optical coupling part between the first and second optical elements And the optical coupling surface of the first optical element protrudes from the surface of the first mount that is fixed to the second mount by the adhesive member and protrudes from the optical coupling portion. A space that prevents the transparent resin from coming into contact with the second mount is formed in the second mount .

The method of manufacturing an optical device according to the present invention includes a first method of fixing the first optical element to the first mount in a state where the optical coupling surface of the first optical element protrudes from a predetermined end surface of the first mount. A fixing step, a second fixing step of fixing the second optical element to the second mount, and the first and second optical elements so that the optical axes between the first and second optical elements are aligned. An optical axis adjusting step of adjusting at least one position and direction, an adhesive member inserting step of inserting an adhesive member between the first and second mounts, an optical coupling surface of the first optical element, and the second A transparent resin insertion step of inserting a transparent resin into the optical coupling portion between the optical coupling surfaces of the optical element, and the second mount is configured so that the transparent resin protruding from the optical coupling portion is the second mount. characterized by including a space so as not to contact the The method of manufacturing an optical device.

  According to the present invention, an optical device in which two optical elements are optically coupled can be manufactured or assembled without requiring a complicated process. Since the stress applied to the optical element can be reduced, the reliability is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a flowchart of an assembly flow of an embodiment of the present invention, FIG. 2 shows an exploded perspective view of the embodiment before assembly, and FIGS. 3 to 7 show side views in respective steps of assembly. Show. FIG. 8 shows a plan view after assembly.

  As shown in FIG. 3, the mount 14 is placed on the vibration isolation table 10 via the fine movement table 12, and the mount 18 is placed via the fine movement table 16. An optical waveguide 22 such as a semiconductor optical waveguide, an optical fiber, or a quartz optical waveguide is fixed to the mount 18 with solder or a cured resin (S1), and an optical semiconductor element 20 such as a laser diode or a light receiving element is attached to the mount 14. It is fixed with solder or a cured resin (S2).

  In FIG. 2, the optical semiconductor element 20 indicated by a solid line is shown before being fixed to the mount 14, and the optical semiconductor element 20 indicated by a broken line is shown after being fixed to the mount 14. Similarly, the optical waveguide 22 shown by a solid line shows before fixing to the mount 18, and the optical waveguide 22 shown by a broken line shows after fixing to the mount 18. The mount 14 is substantially a rectangular parallelepiped, but the mount 18 is provided with a recess 18 a at the center of the surface facing the mount 14. Further, small protrusions 18d and 18e serving as spacers for preventing too close to the mount 14 are provided on the front end surfaces of the protrusions 18b and 18c on both sides of the recess 18a. Since the hardened resin is disposed between the tip portions of the convex portions 18b and 18c and the mount 14 and the mounts 14 and 18 are fixed, the small protrusions 18d and 18e use the hardened resin before hardening of the convex portions 18b and 18c. It also serves to hold between the tip portion and the mount 14.

  When the optical semiconductor element 20 and the optical waveguide 22 are fixed to the mounts 14 and 18, respectively, the optical semiconductor element 20 and the optical waveguide 22 do not need to be actually adjusted in optical axis, and their optical coupling end faces 20a and 22a. Should be facing each other. Further, the end surface 20a of the optical semiconductor element 20 protrudes from the end surface 14a of the mount 14, and the end surface 22a of the optical waveguide 22 is located above the recess 18a. As will be described in detail later, the optical semiconductor element 20 and the optical waveguide 22 are optically coupled above the recess 18a, and the transparent resin 28 is disposed between the end face 20a of the optical semiconductor element 20 and the end face 22a of the optical waveguide 22.

  A mount for mounting an optical element that requires electrical connection such as the optical semiconductor element 20 is provided with an electrode that is electrically connected to the electrode of the optical element by plating or vapor deposition on the surface of the mount.

  As shown in FIG. 4, the mount 18 (and mount 14) is moved on the vibration isolator 10 by the fine adjustment table 16 (and 12), and the optical semiconductor element 20 and the optical waveguide 22 are moved to a distance of about 5 μm. Approach (S4). At the same time, the optical semiconductor element 20 and the optical waveguide 22 are made to have six axes (x, y, z axes) by the fine movement bases 12 and 16 so as to obtain a predetermined or higher optical coupling between the optical semiconductor element 20 and the optical waveguide 22. , X, y, z, rotation about the axis). For example, when the optical semiconductor element 20 is a light emitting element, the optical semiconductor element 20 emits light and the output light of the optical waveguide 22 is monitored. The relative positions and directions of the optical semiconductor element 20 and the optical waveguide 22 are adjusted so that the optical power of the monitoring result is maximized.

  Thereafter, as shown in FIG. 5, the mount 18 is linearly moved on the vibration isolator 10 in the z-axis direction to be separated from the mount 14, and the ultraviolet curable resin 24 is applied to the tip surface portions of the protrusions 18b and 18c (S4). ).

  As shown in FIG. 6, the mount 18 is linearly moved again to bring the optical semiconductor element 20 and the optical waveguide 22 closer to a distance of about 5 μm (S5). At this time, if the ultraviolet curable resin 24 does not contact the mount 14 (S6), the mount 18 is separated from the mount 14 again, and the ultraviolet curable resin 24 is replenished (S4).

  When the ultraviolet curable resin 24 is too much between the mounts 14 and 18, the cured resin 24 may protrude from between the mounts 14 and 18 when the mounts 14 and 18 are brought close to each other. However, in this embodiment, since the recess 18 a is provided, the hardened resin 24 that protrudes does not enter the space for optical coupling between the optical semiconductor element 20 and the optical waveguide 22.

  When the ultraviolet curable resin 24 is sufficient to bond the mounts 14 and 18 (S6), a nozzle 26 is used between the end surface 20a of the optical semiconductor element 20 and the end surface 22a of the optical waveguide 22 as shown in FIG. The fluid transparent resin 28 is dropped (S7). The fluid transparent resin 28 enters between the end face 20a of the optical semiconductor element 20 and the end face 22a of the optical waveguide 22 due to capillary action, and remains there. By using the transparent resin 28 having an appropriate viscosity, the transparent resin 28 stays between the end surfaces 20a and 22a without providing a tray on the lower surface. Moreover, since the downward direction between the end surfaces 20a and 22a is an open space by the recess 18a, even if the transparent resin 28 is dripped excessively, the excess only flows down to the recess 18a and can be easily removed.

  Finally, the cured resin 24 is cured by irradiating with ultraviolet rays (S8). As a result, the mount 14 and the mount 18 are fixed. If necessary, as the transparent resin 28, a cured resin that is cured by heat or ultraviolet rays is used. In the conventional example, since the transparent resin is arranged so as to cover not only the space between the optical semiconductor element 20 and the optical waveguide 22 but also the periphery thereof, the optical semiconductor element 20 or the optical waveguide 22 is deteriorated or damaged by thermal expansion. However, in this embodiment, since the transparent resin 28 exists almost only between the end face 20a of the optical semiconductor element 20 and the end face 22a of the optical waveguide 22, the thermal expansion of the transparent resin causes the optical semiconductor element 20 and the optical waveguide 22 to expand. The optical semiconductor element 20 and the optical waveguide 22 are hardly deteriorated or damaged.

  In this way, the mounts 14 and 18 fixed to each other are removed from the fine movement bases 12 and 16 together with the optical semiconductor element 20 and the optical waveguide 22. Thereby, an optical device composed of the optical semiconductor element 20 and the optical waveguide 22 which are integrated in a state of being well optically coupled can be obtained. FIG. 8 is a plan view of an optical device composed of the optical semiconductor element 20 and the optical waveguide 22 assembled in this manner.

  If the transparent resin 28 has an intermediate refractive index between the refractive index of the core of the optical semiconductor element 20 and the refractive index of the core of the optical waveguide 22, reflection at the both end faces 20 a and 22 a can be suppressed. The transparent resin 28 is optically transparent, and is a fluid resin having a refractive index of the optical waveguide 22 to be used, for example, a refractive index approximate to a refractive index of 1.48 in a quartz waveguide. Silicone resins, epoxy resins, acrylate resins, and the like can be used as the transparent resin 28.

  Even if the transparent resin 28 has fluidity, the transparent resin 28 can be formed into the optical semiconductor element 20 by appropriately setting the viscosity with respect to the distance between the optical semiconductor element 20 and the optical waveguide 22. And the optical waveguide 22. FIG. 9 shows the relationship between the viscosity of the transparent resin 28 and the distance between the optical semiconductor element 20 and the optical waveguide 22, and FIG. 10 shows an enlarged view of a portion having a low viscosity. 9 and 10, the horizontal axis indicates the viscosity (cP) of the transparent resin 28, and the vertical axis indicates the interval (μm) between the optical semiconductor element 20 and the optical waveguide 22.

  If the distance between the optical semiconductor element 20 and the optical waveguide 22 is narrower than the characteristic 40 indicated by the solid line, the transparent resin 28 remains in a state where the space between the optical semiconductor element 20 and the optical waveguide 22 is satisfied, and the optical semiconductor Good optical coupling can be realized between the element 20 and the optical waveguide 22 with low loss. When the interval is wider than the characteristic 42 indicated by the broken line, the transparent resin 28 is completely separated between the end face 20 a of the optical semiconductor element 20 and the end face 22 a of the optical waveguide 22. In the case of the interval between the characteristic 40 indicated by the solid line and the characteristic 42 indicated by the broken line, the transparent resin 28 hangs down between the optical semiconductor element 20 and the optical waveguide 22, and the optical semiconductor element 20 and the optical waveguide 22 The optical coupling between them tends to be unstable and may interfere. 9 and 10, for example, when using a transparent resin having a viscosity of 250 cP, it can be seen that the distance between the end face 20a of the optical semiconductor element 20 and the end face 22a of the optical waveguide 22 must be 100 μm or less. It can be seen that a transparent resin having a viscosity of 86 cP or more should be selected for completeness.

  The curable resin 24 is made of, for example, an epoxy resin, and among the epoxy resins, those having a small shrinkage ratio and a low thermal expansion coefficient upon curing are preferable.

  The transparent resin 28 may be cured between the optical semiconductor element 20 and the optical waveguide 22. For example, the epoxy resin can be cured by ultraviolet rays or heat. Even when the transparent resin 28 is cured, most of the transparent resin 28 is located between the end face 20a of the optical semiconductor element 20 and the end face 22a of the optical waveguide 22, so that the volume is small. As a result, even if the transparent resin 28 is thermally expanded, a large stress is not applied to the optical semiconductor element 20 or the optical waveguide 22. That is, in this embodiment, even if the transparent resin 28 is cured, the possibility that the optical semiconductor element 20 is damaged or deteriorated due to the stress caused by the thermal expansion of the transparent resin 28 due to the heat generated from the optical semiconductor element 20 is low. .

  The transparent resin 28 may be a gel-like resin having flexibility although the fluidity is lowered by ultraviolet rays or heat.

  In the end, the recesses 18a of the mounts 14 and 18 prevent the cured resin 24 and the transparent resin 28 from mixing, and may be any shape that forms such a space. This object can be easily achieved by the configuration of the recess 18a and the protrusions 18b and 18c.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a flowchart of the assembly process of the position Example of this invention. It is a disassembled perspective view of a present Example. It is a side view in the middle of an assembly of a present Example. It is a side view in the middle of an assembly of a present Example. It is a side view in the middle of an assembly of a present Example. It is a side view in the middle of an assembly of a present Example. It is a side view in the middle of an assembly of a present Example. It is a top view after the assembly of a present Example. It is a figure which shows the relationship between the viscosity of a transparent resin, and a space | interval. FIG. 10 is an enlarged view of FIG. 9.

Explanation of symbols

10: anti-vibration table 12: fine adjustment table 14: mount 16: fine adjustment table 18: mount 18a: dents 18b, 18c: convex portions 18d, 18e: small protrusions 20: optical semiconductor element 22: optical waveguide 24: ultraviolet curable resin 26: Nozzle 28: Transparent resin

Claims (7)

A first optical element (20) fixed to the first mount (14);
A second optical element (22) fixed to the second mount (18);
The first and second mounts (14, 18) so that the optical coupling surface (20a) of the first optical element (20) faces the optical coupling surface (22a) of the second optical element (22). ) To fix the adhesive member (24);
Transparent resin (28) that fills the optical coupling portion between the first and second optical elements (20, 22)
Provided with a door,
From the surface where the optical coupling surface (20a) of the first optical element (20) is fixed to the second mount (18) of the first mount (14) by the adhesive member (24). Jumped out,
A space (18a) is formed in the second mount (18) to prevent the transparent resin (28) protruding from the optical coupling portion from coming into contact with the second mount (18). Features optical device. The second mount (18), in claim 1, characterized in that it comprises a convex portion protruding toward both sides in the first mount of the space (18a) (14) and (18b, 18c) The optical device described.   The optical device according to claim 1, wherein the transparent resin is made of a fluid resin.   The optical device according to claim 1, wherein the transparent resin is made of a cured resin. The first optical element (20) is placed on the first mount (14) with the optical coupling surface (20a) of the first optical element (20) protruding from the predetermined end face of the first mount (14). A first fixing step (S1) for fixing;
A second fixing step (S2) for fixing the second optical element (22) to the second mount (18);
Optical axis adjustment step of adjusting the position and direction of at least one of the first and second optical elements (20, 22) so that the optical axes between the first and second optical elements (20, 22) are aligned. (S3),
An adhesive member inserting step (S4, S5, S6) for inserting an adhesive member between the first and second mounts (14, 18);
Transparent resin that inserts transparent resin (28) into the optical coupling portion between the optical coupling surface (20a) of the first optical element (20) and the optical coupling surface (22a) of the second optical element (22). Insertion step (S7)
Provided with a door,
The second mount (18) includes a space (18a) that prevents the transparent resin (28) protruding from the optical coupling portion from coming into contact with the second mount (18). A method for manufacturing an optical device. 6. The method of manufacturing an optical device according to claim 5 , wherein the transparent resin is made of a fluid resin. The method for manufacturing an optical device according to claim 5 , wherein the adhesive member is made of a cured resin, and is cured after the transparent resin insertion step.

Images